1. Field of the Invention
The invention relates to fault tolerant computer systems. More specifically, the invention is directed to a system for providing remote access and control of server environmental management.
2. Description of the Related Technology
As enterprise-class servers become more powerful and more capable, they are also becoming increasingly sophisticated and complex. For many companies, these changes lead to concerns over server reliability and manageability, particularly in light of the increasingly critical role of server-based applications. While in the past many systems administrators were comfortable with all of the various components that made up a standards-based network server, today's generation of servers can appear as an incomprehensible, unmanageable black box. Without visibility into the underlying behavior of the system, the administrator must "fly blind." Too often the only indicators the network manager has on the relative health of a particular server is whether or not it is running.
It is well-acknowledged that there is a lack of reliability and availability of most standards-based servers. Server downtime, resulting either from hardware or software faults or from regular maintenance, continues to be a significant problem. By one estimate, the cost of downtime in mission critical environments has risen to an annual total of $4.0 billion for U.S. businesses, with the average downtime event resulting in a $140 thousand loss in the retail industry and a $450 thousand loss in the securities industry. It has been reported that companies lose as much as $250 thousand in employee productivity for every 1% of computer downtime. With emerging Internet, intranet and collaborative applications taking on more essential business roles every day, the cost of network server downtime will continue to spiral upward.
While hardware fault tolerance is an important element of an overall high availability architecture, it is only one piece of the puzzle. Studies show that a significant percentage of network server downtime is caused by transient faults in the I/O subsystem. These faults may be due, for example, to the device driver, the adapter card firmware, or hardware which does not properly handle concurrent errors, and often causes servers to crash or hang. The result is hours of downtime per failure, while a system administrator discovers the failure takes some action, and manually reboots the server. In many cases, data volumes on hard disk drives become corrupt and must be repaired when the volume is mounted. A dismount-and-mount cycle may result from the lack of "hot pluggability" in current standards-based servers. Diagnosing intermittent errors can be a frustrating and time-consuming process. For a system to deliver consistently high availability, it must be resilient to these types of faults. Accurate and available information about such faults is central to diagnosing the underlying problems and taking corrective action.
Modern fault tolerant systems have the functionality to provide the ambient temperature of a storage device enclosure and the operational status of other components such as the cooling fans and power supply. However, a limitation of these server systems is that they do not contain self-managing processes to correct malfunctions. Also, if a malfunction occurs in a typical server, it relies on the operating system software to report, record and manage recovery of the fault. However, many types of faults will prevent such software from carrying out these tasks. For example, a disk drive failure can prevent recording of the fault in a log file on that disk drive. If the system error caused the system to power down, then the system administrator would never know the source of the error.
Traditional systems are lacking in detail and sophistication when notifying system administrators of system malfunctions. System administrators are in need of a graphical user interface for monitoring the health of a network of servers. Administrators need a simple point-and-click interface to evaluate the health of each server in the network. In addition, existing fault tolerant servers rely upon operating system maintained logs for error recording. These systems are not capable of maintaining information when the operating system is inoperable due to a system malfunction. Existing systems do not have a system log for maintaining information when the main computational processors are inoperable or the operating system has crashed.
Another limitation of the typical fault tolerant system is that the control logic for the diagnostic system is associated with a particular processor. Thus, if the environmental control processor malfunctioned, then all diagnostic activity on the computer would cease. In traditional systems, if a controller dedicated to the fan system failed, then all fan activity could cease resulting in overheating and ultimate failure of the server. What is desired is a way to obtain diagnostic information when the server OS is not operational or even when main power to the server is down.
Existing fault tolerant systems also lack the power to remotely control a particular server, such as powering up and down, resetting, reading system status, displaying flight recorder and so forth. Such control of the server is desired even when the server power is down. For example, if the operating system on the remote machine failed, then a system administrator would have to physically go to the remote machine to re-boot the malfunctioning machine before any system information could be obtained or diagnostics could be started.
Therefore, a need exists for improvements in server management which will result in greater reliability and dependability of operation. Server users are in need of a management system by which the users can accurately gauge the health of their system. Users need a high availability system that must not only be resilient to faults, but must allow for maintenance, modification, and growth--without downtime. System users must be able to replace failed components, and add new functionality, such as new network interfaces, disk interface cards and storage, without impacting existing users. As system demands grow, organizations must frequently expand, or scale, their computing infrastructure, adding new processing power, memory, storage and I/O capacity. With demand for 24-hour access to critical, server-based information resources, planned system downtime for system service or expansion has become unacceptable.